1. Field of the Invention
This invention relates to devices for providing an indication of water or other liquid rising above a pre-determined level. More particularly, the invention relates to an apparatus for placement near a container being filled with liquid, and which provides an audible alarm when the liquid rises to a pre-determined level.
2. Description of Background Art
Filling bathtubs, swimming pools and the like with water to a desired level takes a substantial period of time. For that reason, the person responsible for shutting off the water flow when the water reaches the desired level must be in attendance to observe the filling of the vessel for a long period of time. Alternatively, the person may go about other activities in areas remote from the vessel during the filling operation. But this requires frequent returns to the vessel to check on the filling operation. To eliminate wasted time and energy, it would therefore be desirable to provide means for indicating to a person remote from the vicinity of the vessel being filled with water or other liquid when liquid in the vessel has risen to a pre-determined level.
Other inventors have responded to a perceived need for providing a remote indication when water in a vessel reaches a pre-determined height. Typical prior art inventions providing such an indication utilize a float to close an electrical switch when the float is bouyed to a pre-determined height by water rising in a vessel. The switch is in series with a source of electrical power and an audible alarm, such as a bell, thus providing an audible signal when the water in the vessel reaches a pre-determined level. Examples of prior art water level alarms are disclosed in the following U.S. Pat. Nos.:
Bishop, 741,759, Oct. 20, 1903, Overflow Alarm. PA1 Milo, 3,633,193, Jan. 4, 1972, Warning System for Preventing Overfill in Underground Tanks Having a Gage Box. PA1 Applin, 3,879,771, Nov. 19, 1974, Liquid Level Alarm.
Prior art alarms of the type disclosed in the above-cited patents appear to be more or less effective in performing their intended function. However, prior art alarms each have certain inherent design characteristics which limit their usefulness. Most importantly, none of the prior art alarms has the capability of being used with a wide variety of shapes and sizes of vessels. The liquid level alarm according to the present invention performs efficiently with a wide variety of vessels and has other novel and advantageous features, which are described below.